Apparatus for winnowing tea



Feb. 24, 1953 SUTHERLAND 2,629,491

APPARATUS FOR WINNOWING TEA Filed Aug. 5, 1947 INVENTOR HO WELL.SUTHERLAND I fiiwi 3. H

ATTORNEY Patented Feb. 24, 1953 APPARATUS FOR WINNOWING TEA HowellSutherland, Durban, Natal, Union of South Africa, assignor to J. Lyons &Company Limited, London, England Application August 5, 1947, Serial No.765,191 In Great Britain June 11, 1945 Section 1, Public Law 690, August8, 1946 Patent expires June 11, 1965 6 Claims.

This invention relates to an apparatus for winnowing tea.

A tea winnowing apparatus according to the invention, comprises, aplurality of sloping baffles arranged one below the other in verticallyspaced relationship, means for feeding a continuous stream of tea ontothe topmost baflle, so that it falls in a series of cascades from onebaffle to the next below it, and means for causing air to pass throughthe several curtains of cascading tea so that dust and fine particlesare thereby removed by said air.

More particularly the baflles are arranged in the form of a hollowsubstantially box-like frame and the air currents are arranged to bedrawn through the curtains of cascading tea in an inward and upwarddirection. To achieve this result, a suction conduit from air exhaustingmeans, is arranged to communicate with the interior of said box-likeframe adjacent the top end thereof. Preferably the baliles are circularand they are arranged concentrically, one below the other, so that theseveral curtains of falling tea are each of closed annular formation.

The baffles are preferably in the form of hollow, shallow frusto-conicalsections, so arranged that the interior space is entirely enclosed bythe curtains of cascading tea. To achieve this result, the last orlowest baflle or baflies, is or are inverted to direct the cascading teainwardly, and the lower end of the lowermost baffle forms anunobstructed discharge opening so that tea converges to form a singleconcentrated stream, as it leaves the apparatus.

The said baflles are surrounded in spaced relationship by a protectivehood, which is open as regards its bottom end, to allow the entry of theair for cleaning purposes. The hood also serves to prevent external aircurrents from disturbing the winnowing effect caused by the induced aircurrent passing through the curtains of falling cascading tea.

The tea to be winnowed is fed to the apparatus from an elevated hopper,and means associated therewith are provided for the purpose of adjusting the rate of feed to suit difierent operating conditions.

According to a preferred construction of apparatus for carrying out theinvention, a feed hopper for the tea to be winnowed, is of cylindricalform and surrounds at least the lower end of a vertical air suctionconduit connected to suitable air exhausting means. The said lower endof the air suction conduit, which isconcentrically disposed within thefeed hopper, is flared and said 2 flared end co-acts with the bottomend. of the feed hopper or an extension thereof, for purposes ofregulating the flow of tea passing from the feed hopper to the baflieswhich are arranged one above the other, directly below andconcentrically with respect to said feed hopper. The said bafiies are soarranged that one or two of the topmost of the series is or are arrangedto cause the tea to cascade in an outward direction, while those towardsthe lower end of the apparatus, are so arranged that the tea is causedto cascade inwardly, until the last or lowest baffie forming anunobstructed discharge opening causes the tea to converge to form aconcentrated stream. The

feed is so arranged that the space within the baflles is entirelyenclosed by the cascading tea, so that the suction effect of the airsuction conduit, causes air to be drawn through the cascading tea in aninward and upward direction. The feed is controlled by a movablering-like feed control member surrounding the lower end of the feedhopper and co-acting as regards its bottom end, with the aforesaidflared bottom end of the suction conduit. This feed control ring isarranged to be raised and lowered by simple lever means, so as to varythe distance between its lower end or edge and the top surface of saidsuction conduit flaring. This feed control ring is suspended from thebottom of the hopper, by means of a plurality of pivoted links andadjustment is effected by causing said control ring to be pivotallyrotated, whereby rotation in one di rection causes said ring to rise andincrease the feed while rotation in the opposite direction, to a limitedextent, causes said ring to be dropped and thereby to restrict the flowof tea passing from the feed hopper. Simple lever and link means areprovided for rotating the feed control ring in the direction required. Y

It will be understood from the aforegoing description that the tea, asit falls from one bafile to the other, is caused to bounce and therebychange direction suddenly. This bouncing effect has the added advantagethat it tends to dislodge from the particles of tea, any adhering dirtor extraneous matter, which is thereafter removed by the air currentspassing through the cascading tea. The apparatus is of simpleconstruction and is conveniently made from sheet metal.

To enable the invention to be more clearly understood and carried intopractice, reference is now made to the accompanying drawing, in whichlike reference numerals refer to like parts throughout the severalviews.

In the drawing:

Fig. 1 is a vertical sectional view of a tea winnowing apparatusconstructed according to the invention, and

Fig. 2 is a fragmentary sectional plan view taken on line II--II of Fig.l; and

Fig. 3 is a fragmentary elevation to an enlarged scale showing thesuspension of the feed control ring from the feed hopper.

Referring to the drawing, reference I denotes the lower end of thecylindrical feed hopper, which is mounted above and concentrically withrespect to the three vertically spaced annular bafiles 2, 3 and 4, whichare held in position by the frame members 5. These bafiles, which arepreferably made of sheet metal, are of hollow frusto-conical shape, withthe baflle 2 arranged outwardly and downwardly and the two lower onesarranged inwardly and downwardly so as to direct the flow of teainwardly as clearly shown in Fig. 1, in which the downwardly directedarrows indicate the flow of tea, while the upwardly directed arrowsindicate the paths of the air through the curtains of cascading tea andup into a vertical suction conduit 6. This hood serves to preventexternal air currents from varying the velocities of air through thecurtains of tea and to restrict the volume of air acted upon by conduit6. A sheet metal hood 1, open as regards its bottom end, surrounds theseries of battles.

The conduit 6, which is concentric with the feed hopper I, is providedwith a flaring 8 at its bottom end. This flaring forms the uppermostoutwardly and downwardly directed bafile. The

bottom end of the feed hopper I extends to,

within a short distance of its top side so as to leave an annulardischarge opening for the tea. Control of the size of this opening iseffected by means of the control ring 9, which surrounds and issuspended from the bottom end of the hopper i by means of a plurality ofpivotally connected links l6. Adjustment of the distance of the bottomedge of the control ring 9 from the flaring 8 is efifected by partialrotation of said ring by means of the two connecting links I I leverarms I2, control shaft I3 and the feed control hand lever H, which isassociated with a slotted quadrant plate I5 for fixing purposes. In Fig.3 the full line position shows the control ring 9 partly raised, whilethe broken line outline shows said ring in its substantially closedposition.

A guide ring it is provided to direct the flow of tea from the baffle 8onto the next baflie 2, and a similar guide ring I! is provided todirect the flow from the bafiie 2 onto the third baflle 3.

The suction conduit includes an adjustable extension pipe I8 which isfitted in the lower end of the suction conduit 6. The suction conduit ormore specifically the extension pipe thereof protrudes through the feedhopper I and the uppermost bafiie, coaxially therewith, and ends belowthe lower rim of baffle 8. Said pipe I 8 can be raised or lowered toalter the position of the air intake to vary the distribution of airpassing through the cascading material. The upper end of said pipe I5 isadjustably secured inside the conduit 5 by means of a bolt 2I passingthrough hole in the conduit and a longitudinal slot 28 in the pipe I Ifdesired, the lower end of the pipe It may be flared as shown at I9 bydotted lines.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. An apparatus for winnowing tea comprising a feed hopper, fourfrusto-conical bafiles mounted in vertical arrangement beneath said feedhopper, one above the other, spaced apart, the upper two of said bafliesbeing downwardly and outwardly directed and the lower two baffles beingdownwardly and inwardly directed for forming a concentrated stream ofwinnowed tea leaving the apparatus, the lowermost baflle forming anunobstructed discharge opening a protective hood disposed in closeproximity to the spaces between the bafiles and open at its lower endfor the entry of air into the apparatus, a suction pipe for sucking airthrough the spaces between the baffles, the said suction pipe projectingthrough the feed hopper and the uppermost bafiie and extending below thelower rim of the said bafile, and an axially adjustable extension pipefitting in the lower end of the suction pipe for raising and loweringthe position of the level of the air intake of the extension pipe,thereby varying the distribution of air passing through the teacascading from baffle to baffle, the diameter of the intake opening ofsaid extension pipe being small relative to the maximum diameter of theuppermost bafile.

2. An apparatus for winnowing tea comprising in combination a pluralityof frusto-conical baffles mounted in vertical arrangement, one above theother, spaced apart, the uppermost bafile being outwardly and downwardlyslanted and the lowermost baflie being downwardly and inwardly slanted,a feed hopper mounted above the uppermost baffle for feeding tea to bewinnowed to said baiile, the lower rim of the lowermost baiile formingan unobstructed discharge opening for the winnowed out tea, and asuction pipe for sucking air through spaces between the bailiesprojecting through the feed hopper and the uppermost bafiie andextending below the lower rim of the said baiile, the said suction pipebeing mounted axially adjustable for raising and lowering the positionor the intake opening of the suction pipe relative to the spaces betweenthe baflles, thereby varying the distribution of air passing through thetea cascading from baflle to bafiie.

3. A winnowing apparatus according to claim 2, in combination with anaxially adjustable extension pipe fitted in the lower end of the suctionpipe for varying the level of the intake opening through which air issucked.

4. A winnowing apparatus according to claim 2, wherein locking means areprovided for securing the said suction pipe in a selected axialposition.

5. A winnowing apparatus according to claim 1, wherein axially elongatedguide rings encompass the peripheral lower edges of the two uppermostbaffles radially spaced therefrom, each of said guide rings forming anaxial annular guide channel with the respective baflle.

6. An apparatus for winnowing tea comprising in combination a pluralityof frusto-conical baflies mounted in vertical arrangement, one above theother, spaced apart, the uppermost bafiie being outwardly and downwardlyslanted and the lowermost baffle being downwardly and inwardly slanted,a feed hopper mounted above the uppermost bafiie for feeding tea to bewinnowed to said bailie, the lower rim of the lowermost baffle formingan unobstructed discharge opening for the winnowed out tea, a suctionpipe for sucking air through the spaces between the bafiles projectingthrough the feed hopper and I 5 the uppermost bame, coaxially therewith,and extending below the lower rim of the said baflle, the said suctionpipe being mounted axially adjustable for raising and lowering theposition of the intake opening of the pipe relative to the spacesbetween the baflles, thereby varying the distribution of air passingthrough tea cascading from baflle to baflle, and a protective hooddisposed in close proximity to the spaces between the bafiies and openat its lower end for the entry of air into the apparatus.

HOWELL SUTHERLAND.

REFERENCES CITED The following references are of record in the file ofthis patent:

